The Solution

The original author of GPSBabel, Robert Lipe, needed to convert waypoints between a couple of formats, so he
whipped up a converter and designed it upon an extensible foundation so
that it was easy to add new formats and made the program freely available. Many others have contributed to the program since then.

Most file formats added so far have taken under 200
lines of reasonable ISO C so they can be stamped
out pretty trivially. Formats that are ASCII text delimited in some
fixed way can be added with no programming at all via our
style mechanism.